Biofuels — or the dream of them — have been around almost as long as the engine. Still, more than a century later, biofuels in their many forms are still struggling to gain market share and researchers are still trying to understand their true impact on land use and climate.

We traced the past and present of this alternative energy source in order to divine its future.

Past

The first use of biofuels in engines is often credited to Rudolf Diesel, the inventor of the heat-driven oil engine. In his early demonstrations of the engine, Diesel’s used peanut oil for fuel and famously said, “The use of vegetable oils for engine fuels may seem insignificant today, but such oils may become in the course of time as important as the petroleum and coal tar products of the present time.” Other automotive pioneers were similarly agnostic about fuel type: Henry Ford’s Model T was technically a “flexible fuel vehicle,” meaning it was capable of running on both ethanol and fossil fuel.

Although Diesel and Ford contributed to the adoption of biofuel in engines and machinery, modern day biofuels owe their existence to a lesser known historical figure: G. Chavanne (PDF) from the University of Brussels. Chavanne filed the first known patent in 1937 for a conversion method to turn vegetable oil into a less corrosive motor fuel.

This patent marks the beginning of modern-day biofuel production, because although unadulterated vegetable oils can be used as fuel, over time they cause engine deterioration, and work better once converted to methyl or ethyl esters.

Present

In recent years, the presence of biofuels has increased in a number of industries, including motor fuel processing, train travel and air travel.

Many gas stations today use a blend of biofuel and fossil fuel. Ethanol blends of 10 percent or less are approved for use in any vehicle, and any diesel engine can run on 100 percent biodiesel. The Energy Policy Act of 2005 requires that the use of biofuel in motor fuel be increased from 4 billion gallons in 2004 to a minimum of 7.5 billion gallons in 2012.

Air travel and train travel are the most recent adopters of bioenergy. The use of biofuels in air travel was approved for commercial use in July of 2011. Since then, a number of airlines have flown test flights using biofuels, and one NAVY F/A-18 fighter jet even broke the sound barrier using a half and half mixture of kerosene and biofuel derived from Camelina.

Train travel is also catching on to the use of biofuel. A new start-up aims to restore steam locomotives to run on biocoal, and Amtrak has a train that runs on diesel fuel mixed with biofuel made from beef tallow.

Future

The latest improvements to biofuel currently in the works include a new generation of more efficient and greener biofuels.

This new generation of biofuels will be produced in a variety of different ways. The most viable option available today uses second-generation biomass as a feedstock. Second-generation feedstock is produced from waste products or other non-food items, meaning their use in biofuel production won’t impact food supplies. It is typically developed on marginal lands, further improving its sustainability.

Further technological advancements not yet out of the lab include the use of algae, microbes and even genetically modified E. coli to create biofuels.

Biofuels have experienced great successes as a renewable energy source because their use in existing engines and machinery doesn’t require any retrofitting or additional modifications. As biofuels continue to improve in their efficiency and sustainability, their use is expected to increase.

A recent report by the International Energy Agency estimates that by 2050, these next-generation, sustainable biofuels could account for over a quarter of the world’s total transport fuel (for reference, only about 2 – 4 percent of transportation fuel used today is biofuel). Using more sustainable biofuels would be a big boost for the green economy, and a major step forward in reducing our carbon emissions.